JP2501743B2 - Sealed snap switch assembly and method of refilling its housing chamber with gas - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a switch assembly installed as part of an overall controller for a fluid and powder distribution or storage system, and more particularly to the interior of the switch assembly. This switch assembly is designed to prevent the passage of gas or electric arcs to the outside of the switch and to enhance the performance of such switch assemblies as controls in explosive, corrosive, dusty and wet environments. It is in a completely sealed state.

[0002]

BACKGROUND OF THE INVENTION Within an overall controller for a fluid or powder distribution or storage system, a control switch assembly is commonly used to display key factors such as pressure, fluid flow, powder level, proximity valve position, and the like. used. However, a major problem with this type of device is that some degree of sealing is not achieved with this device.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to not only prevent gas or arc from leaking out of a switch mounting chamber of a switch assembly, but also to prevent explosiveness and corrosion without adversely affecting the operation of the switch. It is to provide a completely sealed switch assembly of the above type to provide a control switch of the above type that can be easily used in wet, dusty and wet environments.

Another object of the present invention is a switch assembly of the above type wherein the switch terminals and the leads connected thereto are hermetically sealed for use when the switch assembly is delivered to the end user. To provide.

Yet another object of the present invention is to fit each pin-type terminal in a novel housing structure of a switch assembly of the type described above that receives a conventional sub-miniature snap switch with protruding pin-type terminals. And a lead wire connected to each of the protruding tubes, and a connecting portion between the protruding tube and the lead wire is covered with a ceramic material. Providing a made housing structure.

A further object of the invention is, in a switch assembly of the type mentioned above, that the switch itself is enclosed in a hermetically sealed housing, which housing is provided with a recess above the switch unit. The outer and inner lever arms are secured to actuate the switch itself in response to movement of the inner lever in the switch chamber formed by the switch housing when a predetermined force is applied to the outer lever. The present invention provides a switch assembly.

Yet another object of the present invention is to evacuate the sealed switch chamber of the housing assembly and then to introduce a gas such as hydrogen, nitrogen, or helium which enhances the life of such sub-miniature snap switches. A method of refilling the switch chamber is provided. Yet another object of the present invention is to provide a switch assembly of the above type by allowing any one of the protruding tubes to be used for evacuation and refill prior to its sealing and then sealing. To provide.

[0008]

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a housing comprising first and second cup-shaped perforated metal housing members, each housing member having a substantially flat bottom wall and an integral side wall. Forming, the side wall extends from the periphery of the bottom wall to an edge portion, and the side wall extending from the bottom wall of the second housing member includes only a portion of the distance that the side wall of the first housing member extends from the bottom wall. And a second housing member sealingly mounted within the first housing member to form a switch mounting chamber between the bottom walls of the respective housing members, the sidewalls of the housing members extending in the same direction. The bottom wall of the second housing member supports the switch, and a plurality of conductive protruding tubes are closely attached to the bottom wall of the second housing member. The projecting terminals of the switch unit are fitted to the projecting tubes, the projecting tubes are brought into close contact with the terminals accommodated therein, and the lead wires are electrically connected to the projecting tubes. An assembly using a porcelain material that covers the connection between a lead wire and the corresponding protruding tube, wherein any one of the protruding tubes of the housing is evacuated and refilled of the switch chamber prior to its sealing. There is provided a hermetically sealed snap switch assembly adapted for use for

The present invention will now be described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited thereto.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The basic object of the present invention is to provide a sealed type used as part of said control system for indicating, for example, pressure, fluid flow and / or level, powder level, proximity, valve position, etc. In providing a snap switch assembly 10. Although the sealed snap switch assembly 10 is widely applied in such control systems, its use in control systems used in explosive, corrosive, dusty, and wet environments will improve its control performance. Can be improved.

In the drawings, reference numeral 10 generally designates a hermetically sealed snap switch assembly according to the present invention, the snap switch assembly 10 comprising a hermetically sealed housing 11 comprising an outer housing member 12 and an inner housing member 14.
These housing members 12, 14 form a hermetically sealed switch chamber 16 within which a conventional snap switch 18 having an actuator 20 (FIGS. 5-7) is operable without a conventional mounting bracket. Installed.

Although the hermetically sealed snap switch assembly 10 shown in the accompanying drawings is a preferred embodiment of the present invention, it is clear that the characteristic feature of this embodiment is that it can be modified by those skilled in the art.

In accordance with the present invention, the switch 18 is a subminiature snap switch type switch having protruding pin type terminals 22, 24, 26 (FIGS. 5-7), which is an Illinois, freeport, honeywell. It is offered as a general snap switch of this type provided by many US companies, such as Micro Switch Division of the same company. Within the inner housing 14, an equal number of open end tubes 28, 30, 32 are sealingly mounted so as to project from the switch chamber 14 such that they connect the respective terminals 22, 24, 26 of the snap switch 18. Snap switch 1 with orientation and size to fit and without mounting bracket, as shown in FIGS. 5-7.
8 is mounted in the chamber 16. Further, the outer and inner housing members 12, 14 are interconnected such that the chamber 16 is sealed along their abutments, and the switch actuator 20 is coupled to the outer lever 34.
Actuated by the outer lever to actuate the inner lever 36 through the housing sealing wall portion 38 to which the levers 34 and 36 are suitably glued or secured. The switch terminals 22, 24, 2
6 is inserted into (mounted in) each housing tube 28, 30, 32, and leads 40, 42, 44 are attached to each housing tube 28, 30.
30 and 32, the outer space of the inner housing member 14 is filled with a suitable porcelain material 48, which comprises the respective leads 40, 42, 44 and the respective tubes 28, 30, 32. Cover and seal the connection part of.

The outer housing member 12 includes a cover 50, which is rectangular dish-shaped or cup-shaped and is formed from a suitable grade of non-perforated steel sheet, the bottom wall 5 thereof.
A side wall 54 extends from 2 to reach an edge portion 56 which surrounds the housing 14. The bottom wall 52 of the outer housing member 12 is essentially flat, except for the recess 58, which forms the sealing wall section 38, which is surrounded by the annular wall section 59. .

An outer lever 34 is externally attached to the outer housing member 12, which has a contact 62 secured to its distal end 60 (FIGS. 5-7), which contact 62 of the outer housing wall portion 38. Welded or otherwise secured to the outer surface. Also, the outer lever 34
The proximal end 64 of the switch operates the snap switch 18. Therefore, the inner lever 36 is provided, and the inner lever 36 is
The distal end of is integral with a contact 68 which is suitably secured to the inner surface of the sealing wall portion 38 of the outer housing member 12. The proximal end 70 of the inner lever 36 operatively engages the actuator member 20 of the snap switch 18.

The levers 34 and 36 are formed of a metal strip having high rigidity. The function of these levers is
This is because the downward thrust force applied to the distal end 64 of the outer lever 34 is transmitted substantially without bending. The levers 34 and 36 are secured to the sealing wall body portion 38 of the housing member 12 and the wall body portion 38 flexes independently of the bottom wall body 52 so that the thrust causes the proximal end 70 of the inner lever 36 to move. The inner lever 36 is thus actuated to depress the switch actuator 20 and actuate the snap switch 18 according to the special construction of the snap switch 18 and the installation of the snap switch assembly 10 in the control system. Therefore, the levers 34, 36 are preferably arranged substantially parallel.

Snap switch 18 may be any suitable sub-miniature snap switch of the type described above with conventional pin type terminals 22, 24, 26.

The outer housing member 12 also includes a pair of spaced apart mounting tubes 72, 74 (FIGS. 5-7), each mounting tube having an open end and traversing the housing member 12. Each end 73, 75,
77, 79 are suitably welded around corresponding openings 78, 80, 82, 84 formed in the side wall 54 of the housing member 12 to provide a seal at those locations. These cross pipes 72 and 74 are used for the snap switch assembly 1
Useful for properly mounting the snap switch assembly 10 by inserting appropriate mounting screws (not shown) through the inside of these tubes and the openings of the fixed structure when installing the zero (of course, the assembly Appropriate nuts or the like can be used for the above screws to hold 10.)

The inner housing member 14 is also rectangular dish-shaped or cup-shaped and is sized to fit inside the edge portion 56 of the outer housing member 12. The bottom wall 90 of the inner housing member 14 (FIGS. 5 to 7)
Is formed integrally with the side wall 92, and the side wall 92 extends from the bottom wall 90 and has an edge portion 94 at its tip. In the present invention, the snap switch 1 is provided on the bottom wall 90.
8 pin-type terminals and the same number of spaced apart openings 96 (FIG. 7) are formed therein, respectively
0, 32 are abutted by glass seals 95, 97, 99, respectively, in the corresponding openings 96 (FIG. 7, this can be done with any suitable type of glass material suitable for sealing). Each tube 28, 30, 32
Are arranged with respect to the inner housing member 14 so that the corresponding switch terminals 22, 24, 26 are fitted therein. A suitable layer or sheet of insulating material insulates the snap switch 18 from the bottom wall 90 of the inner housing member.
0 can be formed by commercially available RTV rubber.
Of course, this insulating layer 100 is applied to the terminals 22, 2 respectively.
The openings are provided corresponding to the directions of 4 and 26. These terminals are connected from the snap switch 18 to the respective tubes 28, 3
This is because it extends to the end of 0 and 32. Therefore, the terminal 1 arranged outside each terminal 22, 24, 26
01 for each tube 28, 30, 32 (103
Soldered to each tube 28, 30,
32 is sealed. Corresponding pin type terminals 22, 24, 26 of the switch 18 mounted in the chamber 16 are inserted into the tubes 28, 30, 32, respectively.
Any one of the tubes 28, 30, 32 may be used to evacuate the chamber 16 and refill with gas that enhances the life of the sub-miniature switch 18, after which the tubes are Sealed.

The "wiring" leads 40, 42, 44 of the snap switch 18 are each a conventional insulating cover 104.
Including a metal conductive core 102, these cores being
Each switch pin type terminal 22, 24, 2 by being properly connected to each tube 28, 30, 32.
Operatively connected to 6. As shown in FIGS. 5-7, this may be accomplished by wrapping each lead core 102 around the corresponding tube 28, 30, 32 by spot welding or soldering (105) or by matching the cores. It is carried out using conventional mechanical equipment, such as "quick connection" or "stake-on" equipment, which is connected onto the tube of the. Lead wires 40, 42, 44 and their respective tubes 2
The other part of the space surrounding the connection with 8, 30, 32 is filled with a suitable porcelain compound 48, which is preferably with these connections and the pipe 28,
The seals 103 between the terminals 30, 32 and the respective terminals and the end portions of the respective lead wire covers 104 are covered.
A preferred porcelain material for this purpose is E available from United Resins, Inc., Santa Ana, California.
L-CAST resin 4123.

As mentioned above, the inner housing member 14 is sized to fit within the side wall 54 of the outer housing member 12 and includes the snap switch 18 and the lead wire 4.
Inner housing member 14 with 0, 42, 44 mounted
Is slid into the rim member 56 of the outer housing member side wall 54 to provide the outer housing member edge portion 5 (prior to loading the porcelain material 48 into the inner housing 14).
The seam between the inner and outer housing members 12, 14 is sealed, such as by welding along 6, for example.

The thus-sealed snap switch assembly 10 is suitable for replacement installation in a control system using a basic series switch (industry standard product).

When a suitable sensor mechanism biases the proximal end 64 of the outer lever 34 counterclockwise via a suitable transmission means (not shown), the contact 62 at the end 60 of the lever 34 is sealed wall portion. Since 38 is biased in the same direction,
The same directional movement of the entire inner lever 36 occurs.

Since the contact point 68 at the end of the inner lever 36 is fixed to the sealing wall portion 38, the direction of movement of this inner lever 36 is the same as that of the outer lever 34, so that the inner lever 36 is actuated. The snap switch 18 is operated according to the specifications that the personnel add to the control system.

The biasing action of the snap switch 18 on the actuator 20 causes the levers 36, 34 to return to their original positions shown in FIGS.

As will be apparent to those skilled in the art, other suitable switches (not shown) may be appropriately placed in place of the illustrated snap switch 18 and to which the proximal end 64 of the outer lever 34 may be placed.
The sealed switch assembly 10 can be operated in the reverse direction by previously displacing it and returning it.

Further, in the present invention, in order to extend the life of the sub-miniature snap switch 18 used,
After the above-mentioned assembly, as described above, the switch chamber 1
It is also conceivable to evacuate 6 and fill it with a gas such as hydrogen, nitrogen or helium. To that end, one of the pipes 28, 30, 32 is not first provided with a hermetic seal 103, and then one end of a suitable flexible conduit is affixed prior to loading the porcelain material 48 into the assembly 10. To the outside protruding end of the unsealed tube, and then to the other end of the conduit by connecting a suitable reversible gas pump or the like to the chamber 16
Eliminate air and other residual gases from the gas, then reverse the pump to remove the gas (hydrogen, nitrogen or helium as described above)
Are supplied to the chamber 16. The flexible conduit is then removed from the tubing of the assembly 10 and the tubing is sealed to the switch terminals contained therein and then the porcelain material 48 is loaded as described above. To complete the assembly 10.

[0028]

A major improvement in accordance with the present invention resides in the use of glass seals on the housing tubes 28, 30, 32 to seal them. Another important improvement is the very existence of the tubes 28, 30, 32, which not only act as sockets for receiving the pin-type terminals of subminiature snap switches, such as switch 18 as a whole, but also their presence. One of the tubes is used to evacuate and refill the switch chamber. Moreover, the mounting structure of this snap switch 18 does not require a mounting bracket.

The present invention is not limited to the above description, but can be arbitrarily modified and implemented within the scope of the gist thereof.

[Brief description of drawings]

FIG. 1 is a side view of a hermetically sealed snap switch assembly according to the present invention showing a structure having a conventional lead wire extending from a lower end thereof to an electronic device to be controlled.

FIG. 2 is a side view of the switch assembly of FIG. 1 on the opposite side.

3 is a bottom view of the switch assembly of FIGS. 1 and 2. FIG.

FIG. 4 is a plan view of the switch assembly of FIGS.

5 is a cross-sectional view taken along line 5-5 of FIG.
The figure which omitted the ceramic material shown in.

FIG. 6 is similar to FIG. 5, but showing a porcelain material.

FIG. 7 is an enlarged view of FIG.

[Explanation of symbols]

 10 Snap Switch Assembly 11 Housing 12 Outer Housing 14 Inner Housing 16 Switch Chamber 18 Snap Switch 20 Actuator 22, 24, 26 Terminal 28, 30, 32 End Opening Tube 34 Outer Lever 36 Inner Lever 38 Sealing Wall Body Part 40, 42 , 44 Lead wire 48 Ceramic material 58 Recessed portion 72, 74 Device mounting tube 95, 97, 99 Glass seal 96 Opening 100 Insulation layer 103 Glass seal

Claims (8)

(57) [Claims] 1. A hermetically sealed snap switch assembly comprising a housing, a sub-miniature snap switch, a first lever, a second lever and a securing means, the housing comprising first and second housings. Each of the housing members partially has a substantially flat bottom wall, the first housing member is imperforate, and the second housing member is the first housing member. Mounted in sealing relation to one housing member, the bottom walls of said housing members being substantially parallel to each other to form said housing, and between the bottom walls of each said housing member. Forming a switch chamber therein, the bottom wall of the second housing member also including a plurality of electrically conductive tubes secured in a sealing relationship, wherein the second housing member is The sub-miniature snap switch is mounted in the switch chamber between the bottom walls of the housing member, the switch facing the bottom wall of the first housing member. A side surface extending into the chamber, the switch includes an actuator member on a side surface of the switch in the chamber, the switch is supported by a bottom wall of the second housing member, and the tubes are respectively One end of the switch projects from the housing in a direction away from the chamber, the switch has a plurality of terminals extending therefrom and received to fit in the tubes, respectively, and the first housing member is A sealing wall body portion that is evenly recessed from the surface of the bottom wall, the first lever being disposed outside the housing; The first lever extends substantially parallel to a side surface of the switch and is fixed to the sealing wall body portion, and the second lever is disposed in the chamber and fixed to the sealing wall body portion. Engaging the actuator member of the switch, the securing means securing the tube in a sealing relationship to a terminal housed therein, the tube comprising one of the securing means. Before the adaptation of
A sealed snap switch assembly for evacuating and refilling the chamber. 2. The first and second housing members are cup-shaped and each housing member includes a side wall in addition to the bottom wall, the side wall extending from the bottom wall to an edge portion of the housing. The side wall extending from the bottom wall of the second housing member,
Since the side wall of the first housing member extends a certain distance from the bottom wall of the first housing member and the second housing member is mounted in the first housing member, the second housing member is the first housing member. The hermetically sealed snap switch assembly of claim 1, wherein the edge portion of each housing member is inserted into a pre-recorded portion of the member and projects from the respective bottom wall in the same direction. 3. The hermetically sealed snap switch assembly of claim 1, further comprising an insulating layer interposed between the switch and a bottom wall of the second housing member. 4. The method according to claim 1, further comprising: a lead wire connected to each of the pipes; and a ceramic material covering a connecting portion of the lead wire to the pipe and an end of the pipe. Sealed snap switch assembly. 5. A lead wire connected to each of said tubes and a connecting portion of said lead wire to said tube are covered, said second wire
The sealed snap switch assembly of claim 1 including a bottom wall of the housing member and a porcelain material that substantially fills the space defined by the side wall. 6. The tubes are respectively disposed in openings in the bottom wall of the second housing member, and the tubes are each provided with a glass seal in the hermetically sealed relationship with the bottom wall of the second housing. The sealed snap switch assembly according to claim 1, wherein the snap snap switch assembly is fixed. 7. A housing comprising first and second imperforate metal housing members, each housing member forming a substantially flat bottom wall and the second housing member being the first.
Mounted in a sealing relationship to the housing members and the bottom walls of each housing member are substantially resistive to each other to form the housing and a switch chamber between the bottom walls. And a snap switch mounted in the switch chamber between side walls of the housing member, the bottom wall of the second housing member being secured to the bottom wall. A sealed snap switch assembly configured to include a plurality of open-ended projecting tubes projecting in a sealed relationship from, wherein the projecting ends of all but one of the projecting tubes are sealed; Sealingly connecting one end of a flexible conduit to a protruding end of a tube, evacuating the housing chamber through the conduit; Refilling the chamber with gas; removing one end of the conduit from the one tube; sealing the protruding end of the one tube; And refilling the housing chamber of the sealed snap switch assembly with gas to enhance the life of the switch. 8. The method of refilling a housing chamber of a hermetically sealed snap switch assembly according to claim 7, wherein the porcelain material is a two-part epoxy resin.